apacheGH-40038: [Java] Export non empty offset buffer for variable-si…

…ze layout through C Data Interface (apache#40043)

### Rationale for this change

We encountered an error when exchanging string array from Java to Rust through Arrow C data interface. At Rust side, it complains that the buffer at position 1 (offset buffer) is null. After tracing down and some debugging, it looks like the issue is Java Arrow `BaseVariableWidthVector` class assigns an empty offset buffer if the array is empty (value count 0).

According to Arrow [spec](https://arrow.apache.org/docs/format/Columnar.html#variable-size-binary-layout) for variable size binary layout:

> The offsets buffer contains length + 1 signed integers ...

So for an empty string array, its offset buffer should be a buffer with one element (generally it is `0`).

### What changes are included in this PR?

This patch replaces current empty offset buffer in variable-size layout vector classes when exporting arrays through C Data Interface.

### Are these changes tested?

Added test cases.

### Are there any user-facing changes?

No

* Closes: apache#40038

Authored-by: Liang-Chi Hsieh <[email protected]>
Signed-off-by: David Li <[email protected]>

java/vector/src/main/java/org/apache/arrow/vector/complex/ListVector.java

@@ -553,21 +553,11 @@ public void splitAndTransfer(int startIndex, int length) {
       Preconditions.checkArgument(startIndex >= 0 && length >= 0 && startIndex + length <= valueCount,
           "Invalid parameters startIndex: %s, length: %s for valueCount: %s", startIndex, length, valueCount);
       to.clear();
-      if (length > 0) {
-        final int startPoint = offsetBuffer.getInt(startIndex * OFFSET_WIDTH);
-        final int sliceLength = offsetBuffer.getInt((startIndex + length) * OFFSET_WIDTH) - startPoint;
-        to.offsetBuffer = to.allocateOffsetBuffer((length + 1) * OFFSET_WIDTH);
-        /* splitAndTransfer offset buffer */
-        for (int i = 0; i < length + 1; i++) {
-          final int relativeOffset = offsetBuffer.getInt((startIndex + i) * OFFSET_WIDTH) - startPoint;
-          to.offsetBuffer.setInt(i * OFFSET_WIDTH, relativeOffset);
-        }
-        /* splitAndTransfer validity buffer */
-        splitAndTransferValidityBuffer(startIndex, length, to);
-        /* splitAndTransfer data buffer */
-        dataTransferPair.splitAndTransfer(startPoint, sliceLength);
-        to.lastSet = length - 1;
-        to.setValueCount(length);
+      to.offsetBuffer = to.allocateOffsetBuffer((length + 1) * OFFSET_WIDTH);
+      /* splitAndTransfer offset buffer */
+      for (int i = 0; i < length + 1; i++) {
+        final int relativeOffset = offsetBuffer.getInt((startIndex + i) * OFFSET_WIDTH) - startPoint;
+        to.offsetBuffer.setInt(i * OFFSET_WIDTH, relativeOffset);
       }
     }